The iPhone 6s is finally out and available in stores. With no shortage of new features, one can make a strong case that this is the most exciting iPhone upgrade in years. While millions of new iPhone users are undoubtedly busy exploring their new devices tonight, some lucky reviewers were granted early access to Apple's next-gen smartphone.

Over the weekend, 13 million people purchased new iPhones. If you haven't yet upgraded and are on the fence about whether or not the new iPhone 6s is for you, there is no shortage of exhaustive iPhone reviews worth checking out. Though just an 'S' upgrade in name, there are so many new hardware and software features in the iPhone 6s to get excited about. From 3D Touch to crazy new camera functionality, the iPhone 6s looks like an all-around amazing device.

But again, don't take my word for it. Check out some of these reviews from folks who have already been using the device for two-plus weeks.

But 3D Touch, the most significant of the iPhone 6s’s tentpole features, is. Easily. Built on a system of sensors that detect touch pressure across the face of the iPhone 6s’s display, 3D Touch triggers pop-up menus and previews based on how firmly you press down. Currently, it supports two interactions “peek” and “pop,” with peek calling up a preview of an app or message, or a brief contextual menu, and pop launching the app itself. Each interaction is accompanied by a different tiny vibration that helps you distinguish between them. It is surprisingly useful — particularly for power users who do a lot of work from their iPhones. I’m already using it constantly, and I am impressed with how good it is at interpreting the force of my touch. It’s very much an Apple innovation — a seemingly subtle change so thoughtfully executed that it proves transformative.

Does that also sound like Jobsian hyperbole? Probably. But I think 3D Touch is likely the biggest innovation to the iPhone UI since the iPhone UI. And it’s largely why the answer to the question I posed earlier is “yes.”

Apple as ever may not lead the market on individual points - its screen isn't QHD, its battery is behind Sony's Xperia Z5 and its camera is paralleled by Samsung's Galaxy S6 - yet the iPhone 6S is a great phone. As ever, it's not in specifics but in the overall package where the firm remains without rival, creating a comprehensive mobile powerhouse with the most comprehensive App Store and no major shortcomings.

So I'm just going to put this out there, and then we can all handle the emotional consequences together: if you are thinking of buying a new phone, and you have anything older than an iPhone 6, you should buy an iPhone 6S Plus. It is the best iPhone ever made, and it is right now the best phone on the market. If you're upgrading from an iPhone 5S or anything older, it will blow your mind. There just aren't other companies that can roll out a feature like 3D Touch and make it work in a way that suggests the creation of entirely new interface paradigms, and every other phone maker needs to figure out exactly why Apple's cameras are so consistent before they can really compete.

David Pogue of Yahoo was a fan of the iPhone 6s, but notes that it may not be worth the upgrade if you have an iPhone 6:

The iPhone 6 was already a spectacularly great phone. If you’d have to pay an early-termination fee to get the iPhone 6s, it’s probably not worth upgrading to the 6s.

But if you have any older iPhone model, or if you’re paying monthly for one of those “switch phones whenever without penalty” programs, or if you’ve been poised waiting for the right moment to jump into the iPhone parade, then the iPhone 6s might be singing your name. The speed and the 3D Touch features are the meat of the upgrade. The rest is just “s” gravy, but really delicious gravy.

It's a fair point, but having been using 3D Touch myself over the past few days, I personally think that it's a killer feature that is well worth the upgrade. Indeed, it represents the first useful advancement in UI interaction on mobile in years.

Lance Ulanoff of Mashable touches on the new Hey Siri feature which lets users activate Siri with a voice command even when your device isn't plugged in.

With iOS 9, Apple’s iPhone now achieves parity with Android’s “OK Google,” responding to “Hey Siri” even when locked and too far away for me to touch. I did have to train Siri on my voice, which is an easy three- or four-step process. Once that was done, I could call “Hey Siri” from across the room and Siri would wake up the phone, ready to listen.

I could ask about the weather, news and my schedule. I could also ask her to manage system settings like turning off Bluetooth. She can’t access every setting. I tried asking Siri to change my phone’s screen brightness, but she couldn’t and instead offered me a direct link to the phone’s display settings. Siri is trained on my voice so others cannot wake her up...

For those with an iPhone 6 or 6 Plus, the new 3D Touch and Live Photos perks aren’t substantive enough to make it worth upgrading to a 6s. While Apple improved the camera resolution and designed the 6s and 6s Plus with stronger metal and glass than the last iPhones, a major component — battery life — was not improved. It would be wiser to hold off until the next version, which will most likely include more significant improvements.

Of course, with the new iPhone models now out and available in stores, if you're at all curious about what Apple has managed to pack into its next-gen iPhone, definitely make a trek down to your local Apple retail store and give 3D Touch a try. It's a transformative UI paradigm that will really explode in functionality once developers start implementing it across their apps.

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Yoni Heisler is a technology writer and Mac nerd who's been using Apple products for well over 21 years. He actively covers a wide variety of Apple topics, from legal news and rumors to current events and even Apple related comedy and history.